package cn.tedu.sp06.fallback;

import cn.tedu.web.util.JsonResult;
import org.springframework.cloud.netflix.zuul.filters.route.FallbackProvider;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.client.ClientHttpResponse;
import org.springframework.stereotype.Component;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.charset.StandardCharsets;

/**
 * 作用：通过 zuul 网关，调用后台商品服务失败时。
 * 会执行这段降级代码，向客户端返回降级结果
 */
@Component
public class ItemFB implements FallbackProvider {

    /**
     * 设置当前降级类，是针对哪个服务的降级类
     * -item-service: 只针对商品服务降级
     * -* : 针对所有服务都应用当前降级类
     * -null : 和*相同
     */
    @Override
    public String getRoute() {
        return "item-service";
    }

    /**
     * 发送给客户端的降级结果，封装在 response 对象中
     * @param route
     * @param cause
     * @return
     */
    @Override
    public ClientHttpResponse fallbackResponse(String route, Throwable cause) {
        return new ClientHttpResponse() {
            @Override
            public HttpStatus getStatusCode() throws IOException {
                return HttpStatus.INTERNAL_SERVER_ERROR;
            }

            @Override
            public int getRawStatusCode() throws IOException {
                return HttpStatus.INTERNAL_SERVER_ERROR.value();
            }

            @Override
            public String getStatusText() throws IOException {
                return HttpStatus.INTERNAL_SERVER_ERROR.getReasonPhrase();
            }

            @Override
            public void close() {

            }

            @Override
            public InputStream getBody() throws IOException {
            //JsonResult  {code:500,msg:"调用商品服务失败",data:null}
                return new ByteArrayInputStream(JsonResult.err().code(500).msg("调用商品服务失败").toString().getBytes("UTF-8"));
            }

            @Override
            public HttpHeaders getHeaders() {
                //Content-Type:application/json;charset=UTF-8
                HttpHeaders httpHeaders = new HttpHeaders();
                httpHeaders.add("Content-Type","application/json;charset=UTF-8");
                return httpHeaders;
            }
        };
    }
}
